android 开发edittext获取焦点时hint消失

verifycode= (EditText)findViewById(R.id.verifycode);
        verifycode.setOnFocusChangeListener(new View.OnFocusChangeListener() {
            @Override
            public void onFocusChange(View v, boolean hasFocus) {
                EditText _e = (EditText)v;
                if(!hasFocus)  //没有焦点
                {
                    _e.setHint(_e.getTag().toString());
                }
                else  //获取到焦点
                {
                    _e.setTag(_e.getHint().toString());
                    _e.setHint("");
                }
            }
        });